With 15 years in the industry, Melinda Plemel is well versed in email happenings. She has experience working at ESPs, as well as working with Mailbox Providers, she is currently an active member of M3AAWG (www.MAAWG.com) participating in several global projects. Melinda has been working at Return Path for 9 years and is currently the Senior Industry Advocate and is responsible for managing global partners that join Return Path's Data Exchange program and emerging markets. She is the key to helping and educating Return Path on mailbox providers, anti-spam, and email technology trends, as well as to educating receivers about everything Return Path has to offer. When Melinda isn't helping to make the world safer for email, she spends her time volunteering for Habitat for Humanity, Rocky Mountain Puppy Rescue and riding her Harley through the mountains of Colorado.

This is the first in our series of Marketer's Field Guides to ISPs and Deliverability.

Yahoo! Mail was one of the first free webmail providers to hit the market and is one of the three largest providers in the world with 280+ million users. If you include some of the smaller providers that utilize the Yahoo! infrastructure such as AT&T and BellSouth there are 320+ million users. Even though they are one of the oldest and biggest ISPs in the market they have continued to attract and cater to a relatively young social audience compared to other free webmail providers. Yahoo!’s anti-spam team is also one of the most active and responsive groups in the industry when it comes to clear communications and responsiveness to senders.

Let’s break down some of the key characteristics of this ISP that marketers should know about:

Spam filtering. Yahoo! builds the majority of their spam algorithms in-house. They put a heavy emphasis on content and URL filtering and spam complaints from its users. They are one of the few ISPs that filter email by domain versus only IP address.

Feedback loops. Yahoo! provides a great service to senders by providing feedback loops (FBLs) by individual domain. When a user hits the ‘Spam’ button on their web browser, those marketers who have signed up for FBLs will receive an email with the user’s email address. We recommend that you suppress that user immediately from future mailings to maintain a positive reputation with Yahoo!. Note that DomainKeys or DKIM authentication is a requirement to sign up for FBLs.

Prioritized Delivery. Yahoo! offers legitimate bulk mail senders who maintain good sending reputation the privilege of prioritized deliveries. There are 2 kinds of priority listings. The first is Yahoo!’s internal whitelist that senders can sign up for free. This whitelist is still subject to certain filters including user level filtering and content and URL filtering but we highly suggest that you sign up for this whitelist after you have about a month’s worth of sending history. In addition, Yahoo! subscribes to Return Path’s Certified whitelist, helping them to ensure that legitimate email can get delivered, while also allowing them to aggressively target spam without the concern of blocking the permission-based email consumers want.

Sending reputation. Your reputation is critical in determining inbox or bulk folder placement and is driven by many factors including unknown user rates, spam complaints and known bad addresses or spam traps. You should know that a sender’s reputation is made up of a combination of IP Address +

Domain + From Email Address so it’s important that you maintain consistency in all three of these components since changing any one of these may lower your reputation and degrade your ability to get to the inbox.

Engagement. Engagement has always been an important measure of subscriber interest for senders, but ISPs are starting to make significant investments in research, in-house spam filters and third-party software to help measure subscriber engagement to better determine appropriate folder placement. Factors being considered include what messages are opened, what messages are moved between folders and how quickly mail is deleted. So what can you do about this? Get back to basics. Send relevant email that your subscribers want by tracking opens, clicks and conversions. If you have a large number of subscribers that have never opened or engaged with your mail then it’s time to take a second look at those addresses and determine if you can win them back or let them go. Inactive subscribers will ultimately hurt your ability to get delivered at all ISPs.

Sending Infrastructure requirements. Authenticating email with SPF and DKIM is recommended. Yahoo! has just announced that they now utilize both DKIM and SPF. Servers should be configured to allow for simultaneous connections with throughput set at 20 emails per connection. Rate limiting will occur for high complaints and poor reputation, so use this as a guideline to determine what the optimal setting for you should be.

Partners. Yahoo! has several partners including AT&T (which includes BellSouth, SBC and Ameritech), Verizon, Rogers, BT, TNZ, and Nokia, who utilize Yahoo!’s infrastructure for its customers’ email. AT&T and Verizon will filter mail at their gateways before it is sent to be processed by Yahoo!’s filters, but we have found email sent to these partners should have inbox placements rates that are consistent with direct Yahoo! users.